The present invention relates generally to voltage-controlled oscillators, which are commonly referred to as "VCO's". This invention particularly relates to an improved construction for low-cost VCO's fabricated from discrete components on a printed circuit board and suitable for use in the microwave frequency band, e.g., one GHz and higher.
VCO's are used in a variety of electronic communication devices such as FM detectors, radio and television tuners, and the like. VCO's have typically operated in the MHz frequency range, but with the increasing number of television channels, operating at frequencies of up to 900 MHz and above, it has become increasingly desirable to have VCO's that operate at higher frequency levels, including the microwave frequency range. Such oscillators are readily available if cost is no object, but the challenge is to provide such an oscillator at a cost low enough to make it economically feasible for use in such highly cost-competitive markets as consumer electronics. These markets require not only low cost, but also highly reliable performance over a long operating life.
It is, therefore, a primary object of the present invention to provide a high-frequency (e.g., one to two GHz) VCO which can be mass produced at a low cost while at the same time providing highly reliable operation and a long operating life.
It is another important object of this invention to provide such a high-frequency VCO which can be fabricated on a printed circuit board using a small number of components in a small space.
A further object of the invention is to provide such an improved VCO which can be easily tuned both during production and during operation.
Other objects and advantages will be apparent from the following detailed description in the accompanying drawings.